frequencies obtained in the fast Fourier transform of the input signal (see the Algorithm
section of frestimate).
Superposition Signals
Superposition signals are available only for online estimation with the Frequency
Response Estimator block. For frequency response estimation at a vector of frequencies ω
= [ω 1 , ... , ωN] at amplitudes A = [A 1 , ... , AN], the superposition signal is given by:
Δu=∑
iAisinωit.The block supplies the perturbation Δu for the duration of the experiment (while the
start/stop signal is positive). The block determines how long to wait for system transients
to die away and how many cycles to use for estimation as shown in the following
illustration.
Texp is the experiment duration that you specify with your configuration of the start/stop
signal (See the start/stop port description on the block reference page for more
information). For the estimation computation, the block uses only the data collected in a
window of NlongestP. Here, P is the period of the slowest frequency in the frequency vector
ω, and Nlongest is the value of the Number of periods of the lowest frequency used for
Estimation Input Signals